Shell Cleanup - Githubissues

Refactor the html/js shell to keep webgpu_app.html as close to the qt default shell as possible. Additionally, add some performance improvements.

[x] Shell should not be visible (per default) in release and log is not written to dev log (console.log is slow)
[x] Custom JS (Input Handler, custom webgpu functions) should be moved into a separate file
[x] CSS-Code should be moved into a separate file

weBIGeo / webigeo